1. Field of the Invention
The present invention relates in general to an apparatus and a method for folding a sheet material, and more specifically to an apparatus for fan-folding an electrode sheet and a method of the same.
2. Prior Art
The use of fan-folded lithium based cells is known in the art. Generally, fan-fold lithium based cells comprise a single layered material (including a current collector, anode, cathode and separator) which are “fan-folded” (i.e. accordion folded) to define a stack of cells in a zig-zag configuration. While such fan-fold cells are known, there have been notable difficulties associated with their manufacture.
There are a number of known methods of manufacturing fan-fold batteries, none of which have been adequate to date. Winding manufacturing processes do not allow the production of free form batteries. And while some free form batteries may be produced using a stacking manufacturing process, the number of configurations is still limited and the stacking process is inherently slow. Other conventional processes for manufacturing fan-fold cells are known, but such processes are also slow, inefficient, and often damage the finished product. For example, conventional processes do not maintain the electrode assembly in a fixed position so as to prevent displacement during the manufacturing process. This displacement often results in inaccurate folding and damage to current collector material at the folding line. Additionally, other processes do not provide mechanical support at the folding line of the electrode assembly, thus the current collector does not fold according to the folding direction and is damaged.
Accordingly, it is an object of the present invention to provide an apparatus and a method for folding a sheet material, preferably an electrode sheet, which enables the rapid production of fan-fold batteries, substantially free of defects.
These and other objects will become apparent in light of the present specification, drawings and claims appended hereto.